CESIUM-137 IRRADIATOR SHARED RESOURCE PROJECT SUMMARY/ABSTRACT The Cesium-137 Irradiator Shared Resource was established in 1991 to provide accurate, convenient and reliable access to ionizing radiation to Yale University investigators for irradiations of molecular compounds, cell cultures, animal and human tumor cells, and whole animal experiments. It continues to serve as a valuable research tool for researchers who are studying the effects of radiation on biological samples, animals, and cells in culture or are using radiation as part of their experiments to create mutations for studying the biologic effect of radiation, of mutations themselves, or for immunosuppression. Given the concentration of investigators at Yale studying DNA, it is an essential resource. The Cesium-137 Irradiator offers a wide range of dose rates, collimation and a controlled environment for irradiation samples. Approximately 32 YCC investigators per year have used this device in the last 5 years, to provide precise irradiation to any sample, whether biological or chemical. During our most recent funding period (FY17), 31 people used the Cesium-137 Irradiator. Twenty of these users (65%) were YCC members who accounted for 83% of total resource use. The majority of this use came from Genomics, Genetics and Epigenetics (GGE), Cancer Immunology (CI), and Virus and Other Infection-associated Cancers (VOIC). The Cesium-137 Irradiator Shared Resource serves as a central resource for irradiation and brings a high level of expertise in radiation research to the members of YCC. The results from the many basic research studies that involved the Cesium-137 Irradiator have enabled YCC physicians to improve their ability to detect and treat cancer efficaciously. Ravinder Nath, PhD, (RR), has served as the Director of the Cesium-137 Irradiator Shared Resource since its inception. The Specific Aims of the Cesium-137 Irradiator Shared Resource are to provide: (1) Access to a state-of-the- art Cesium-137 Irradiator, cost-effective irradiator services, and highly skilled technical assistance to all YCC members; (2) Consultation on the design of experiments involving the Cesium-137 Irradiator; (3) Training for the staff of YCC members on the use of the Cesium-137 Irradiator; and (4) Irradiator availability 24 hrs/day, 365 days/year for any cancer investigator whose research requires gamma irradiation.